1. Field of the Invention
The present invention relates to a support fixture for supporting a refrigerant sampling tube in a closed loop refrigeration circuit.
2. Description of the Prior Art
Recently systems have been developed which allow sampling of air or other gaseous compositions such as refrigerants in order to detect the presence of impurities therein. Such systems utilize gas detection tubes filled with various chemical reagant materials for detecting such impurities and contamination. The detection or sampling tubes are typically used in combination with a pump for drawing the gaseous composition being tested through the tubes at a predetermined flow rate to provide an indication of the presence of impurities as well as to provide a measure of the concentration of the impurity over a given test sampling time.
Most gas detection tubes are designed in the form of an elongated cylindrical enclosure of transparent material such as pyrex glass into which the indicating reagent materials are placed before the opposite ends are drawn and sealed.
U.S. Pat. No. 4,923,806 entitled Method and Apparatus for Refrigerant Testing in a Closed System is assigned to the assignee of the present invention and is directed to a method and apparatus for detecting contaminants in a refrigerant medium. This patent teaches the use of single use transparent glass testing tubes which are sealed until used and which contain therein an oil removal section, a water removal and indicating section and an acid indicating section. In use the ends of the glass testing tube are broken off and the tube is placed in a tube holder apparatus which functions to seal the tube so that all the refrigerant flow is directed through the tube. The presence of contaminants is indicated by a color change which may be quantified by comparison to a color chart and/or the extent of the promulgation of the color change in the indicating media.
The holder for the sampling tube disclosed in the '806 patent is adapted to allow a flow of refrigerant to be tested to pass therethrough and then vents it to the atmosphere. The venting of refrigerant gas to the atmosphere is not considered to be an environmentally acceptable expedient.
Other holder devices for gas detection tubes are shown and described in U.S. Pat. No. 4,159,304 Portable Gas Detection Tube Holder and U.S. Pat. No. 4,389,372 Portable Holder Assembly for Gas Detection Tube. Both of the above cited patents incorporate threaded fittings which must be disassembled in order to change the sampling tube contained therein.
A refrigerant purity sampling arrangement has recently been developed wherein a refrigerant puriity sampling tube is mounted in a parallel fluid flow relationship with a refrigerant compressor which operates to provide a pressure differential which provides the necessary fluid flow through the sampling tube to test the purity of refrigerant in the refrigeration system of which the compressor forms a part. This testing system forms the subject matter of a separate United States patent application entitled Method and Apparatus For Sampling the purity of refrigerant flowing through a refrigeration circuit which is assigned to the assignee of the present application and is filed on even date herewith.